This invention relates to a ceiling vent for releasing heat from a room to reduce the temperature in the room to thereby enhance comfort and reduce the load on energy-consuming air-conditioning units. The vent has a safety feature that causes it to close when the temperature in the vent becomes hot enough to indicate a fire or when it is subject to a shock indicative of an explosion. The vent can be used in any room that becomes uncomfortably hot, especially rooms with sun exposure and kitchen with heating-releasing appliances such as refrigerators, stoves, and ovens.